Trends

…        ÝIn the prevaccine era ( before 1995) there were an estimated 3 to 4 million cases of chicken pox per year in the US

…        60 million estimated cases worldwide per year

…        ÝOut of the 3-4 million cases there were 10, 000 hospitalizations per year

…        Ý2 of 1000 hospitalizations were children, while 8 of 1000 were adults

…        Adults are at an estimated nine-fold higher risk than children at being hospitalizedÝÝ

…        Complications involved in hospitalization include pneumonia, encephalitis and othersÝ

…        In the span between 1990-1996 there were a reported 103 deaths

…        Eighty-five percent of the annual number of cases of chicken pox in the US are children less than fifteen years oldÝ

…        Thirty-four percent are aged 4-5, 18% aged 6-10, 6% aged 11-19, and only 4% aged 20-29 yearsÝ

…        In the past, 39% of all cases, the highest percentage, were aged 5-9

…        Recent yearsí statistics have seen a shift to the highest percentage being in the age group 1-4 years, most likely due to the increased use of day care settings and the high transmission in those environmentsÝ

…        Varicella tends to be infectious mostly in temperate environments, especially in children.Ý In temperate regions only 5% of children do no get infected by age 8, whereas a full 50% of children living in the tropics do not get infected by the same ageÝ

…        It is more common in adults in the tropics than in adults of temperate regions.